/*
 * Notifications Database
 */

package edu.gmu.projects.fireresponder.gui;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

/**
 * Simple notifications database access helper class. Defines the basic CRUD
 * operations and gives the ability to list all notifications as well as
 * retrieve or modify a specific notification.
 * 
 */
public class NotificationsDbAdapter {

	public static final String KEY_ROWID = "_id";
	public static final String KEY_ADDED_ON = "added_on";
	public static final String KEY_TITLE = "title";
	public static final String KEY_BODY = "body";

	private static final String TAG = "NotificationsDbAdapter";
	private DatabaseHelper mDbHelper;
	private SQLiteDatabase mDb;

	/**
	 * Database creation sql statement
	 */
	private static final String DATABASE_CREATE = "CREATE TABLE notifications ("
			+ "_id INTEGER PRIMARY KEY AUTOINCREMENT, "
			+ "added_on TIMESTAMP NOT NULL DEFAULT current_timestamp, "
			+ "title TEXT NOT NULL, " + "body TEXT NOT NULL);";

	private static final String DATABASE_NAME = "notificationsdata";
	private static final String DATABASE_TABLE = "notifications";
	private static final int DATABASE_VERSION = 3;

	private final Context mCtx;

	private static class DatabaseHelper extends SQLiteOpenHelper {

		DatabaseHelper(Context context) {
			super(context, DATABASE_NAME, null, DATABASE_VERSION);
		}

		@Override
		public void onCreate(SQLiteDatabase db) {

			db.execSQL(DATABASE_CREATE);

		}

		@Override
		public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
			Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
					+ newVersion + ", which will destroy all old data");
			db.execSQL("DROP TABLE IF EXISTS notifications");
			onCreate(db);
		}
	}

	public void clearDb() {
		mDb.execSQL("DROP TABLE IF EXISTS notifications");
		mDbHelper.onCreate(mDb);
	}
	
	/**
	 * Constructor - takes the context to allow the database to be
	 * opened/created
	 * 
	 * @param ctx
	 *            the Context within which to work
	 */
	public NotificationsDbAdapter(Context ctx) {
		this.mCtx = ctx;
	}

	/**
	 * Open the notifications database. If it cannot be opened, try to create a
	 * new instance of the database. If it cannot be created, throw an exception
	 * to signal the failure
	 * 
	 * @return this (self reference, allowing this to be chained in an
	 *         initialization call)
	 * @throws SQLException
	 *             if the database could be neither opened or created
	 */
	public NotificationsDbAdapter open() throws SQLException {
		mDbHelper = new DatabaseHelper(mCtx);
		mDb = mDbHelper.getWritableDatabase();
		// Empty notifications table to start afresh if needed
		// mDb.execSQL ("Delete from notifications");
		return this;
	}

	public void close() {
		mDbHelper.close();
	}

	/**
	 * Create a new notification using the title and body provided. If the
	 * notification is successfully created return the new rowId for that note,
	 * otherwise return a -1 to indicate failure.
	 * 
	 * @param title
	 *            the title of the notification
	 * @param body
	 *            the body of the notification
	 * @return rowId or -1 if failed
	 */
	public long createNote(String title, String body) {
		ContentValues initialValues = new ContentValues();
		initialValues.put(KEY_TITLE, title);
		initialValues.put(KEY_BODY, body);

		return mDb.insert(DATABASE_TABLE, null, initialValues);
	}

	/**
	 * Delete the notification with the given rowId
	 * 
	 * @param rowId
	 *            id of note to delete
	 * @return true if deleted, false otherwise
	 */
	public boolean deleteNote(long rowId) {

		return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
	}

	/**
	 * Return a Cursor over the list of all notifications in the database
	 * 
	 * @return Cursor over all notifications
	 */
	public Cursor fetchAllNotes() {
		return mDb.query(DATABASE_TABLE, new String[] { KEY_ROWID, KEY_TITLE,
				KEY_BODY }, null, null, null, null, "added_on DESC");
	}

	/**
	 * Return a Cursor positioned at the notification that matches the given
	 * rowId
	 * 
	 * @param rowId
	 *            id of notification to retrieve
	 * @return Cursor positioned to matching notification, if found
	 * @throws SQLException
	 *             if note could not be found/retrieved
	 */
	public Cursor fetchNote(long rowId) throws SQLException {
		Cursor mCursor = mDb.query(true, DATABASE_TABLE, new String[] {
				KEY_ROWID, KEY_TITLE, KEY_BODY }, KEY_ROWID + "=" + rowId,
				null, null, null, null, null);

		if (mCursor != null) {
			mCursor.moveToFirst();
		}

		return mCursor;
	}

	/**
	 * Update the notification using the details provided. The notification to
	 * be updated is specified using the rowId, and it is altered to use the
	 * title and body values passed in
	 * 
	 * @param rowId
	 *            id of notification to update
	 * @param title
	 *            value to set notification title to
	 * @param body
	 *            value to set notification body to
	 * @return true if the notification was successfully updated, false
	 *         otherwise
	 */
	public boolean updateNote(long rowId, String title, String body) {
		ContentValues args = new ContentValues();
		args.put(KEY_TITLE, title);
		args.put(KEY_BODY, body);

		return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
	}
}
